gistfile1.txt

#!/usr/bin/env julia

import LibArchive

# Load the moby dick source into one buffer
moby = read("mobydick")

# Generate random fuzz mutation
mutate(genome) = (genome .+ sprand(UInt8, size(genome)[1], .000001)) .% 256 

patch(original, genome) = (original .+ genome) .% 256

crossover(gen1, gen2) = map(a->rand(0:1)==0?gen1[a]:gen2[a], 1:size(gen1))

function fitness(genome)
	mempt = Vector{UInt8}()
	memptwriter = LibArchive.Writer(mempt)
	LibArchive.add_filter(memptwriter, LibArchive.FilterType.COMPRESS)
	LibArchive.add_filter(memptwriter, "lzma")
	entry = LibArchive.Entry(memptwriter)
	LibArchive.set_pathname(entry, "a")
	LibArchive.set_size(entry, size(moby)[1])
	LibArchive.set_perm(entry, 0o644)
	LibArchive.set_filetype(entry, LibArchive.FileType.REG)
	LibArchive.write_header(memptwriter, entry)
	write(memptwriter, patch(moby, genome))
	LibArchive.finish_entry(memptwriter)
	compsize = size(mempt)
	diff = nnz(genome)
	return diff - 2*compressed
end